1. Field of the Invention
This invention relates in general to loudspeakers, and more particularly, to improved loudspeaker mounting configurations.
2. Prior Art
High frequency transducers or loudspeakers, whether a tweeter (generally considered 5,000 hertz frequency) or a woofer (generally considered 0-5,000 hertz frequency), typically include a permanent magnet for generating a magnetic field, and a yoke assembly consisting of yoke, magnet and plate pieces for focusing the magnetic field to an air gap in which the field is particularly intensified. A voice coil is suspended in the air gap so as to be able to vibrate. A current is passed through the voice coil, and the interaction of the magnetic field created by the current and the magnetic field from the permanent magnet causes the voice coil to vibrate. Attached to the voice coil is a diaphragm which has a large surface area to cause air in the vicinity of the diaphragm to vibrate, thus creating sound.
To obtain high quality sound it is important that the voice coil be disposed in the center of the air gap and not touch the yoke so that the voice coil can vibrate freely. To achieve this arrangement it is important that the relative positions of the pole pieces be rigidly fixed. Typically, plate pieces have been glued, cemented or bolted to the permanent magnet thus rigidly setting the width of the air gap.
To protect the permanent magnet from chipping and to overcome cementing problems it is typical for the permanent magnet and yoke to be encapsulated in plastic or the like.
In most typical configurations a non-magnetic rigid mounting plate is bolted to the enclosed magnet assembly. The diaphragm and the voice coil are attached to and suspended from the plate. Electrical leads from the voice coil are attached to terminals on the plate, to form a complete loudspeaker. The loudspeaker is then mounted to an enclosure forming a portion of a loudspeaker system.
While these systems do reduce the structure necessary to position the yoke and the permanent magnet, the remainder of the structure tends to be bulky due to the necessity of the mounting plate. In addition, since the voice coil must be accurately centered within the air gap the operation of bolting the mounting plate to the enclosed assembly becomes critical, and thus time consuming and expensive.
To overcome some of these problems U.S. Pat. No. 4,507,800 discloses the use of a housing having a quick bayonet type locking mechanism for locking the housing to the mounting plate, a circumferential groove which provides a receptacle for the loudspeaker grill, and a conduit through which conductors can pass to provide an electrical signal to the voice coil. Thus this design attempts to use the bayonet type locking mechanism between the housing and the mounting plate to achieve not only a quick assembly of the loudspeaker, but also utilization of a less bulky mounting plate without reducing the accurate positioning of the voice coil. While this design has reduced some of the prior art problems, there is still need to further simplify installation and assembly to more easily achieve alignment of the electrical contact members with the PC board, provide for greater portability of the loudspeaker by providing easier disassembly of the loudspeaker from the mounting plate, and further decrease the bulk of the loudspeaker and mounting plate assembly.